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US 9,854,275 B2Granted
Quantization in video coding
AssigneeQUALCOMM Incorporated
InventorsRajan Laxman Joshi, Xianglin Wang, Geert Van der Auwera, Marta Karczewicz
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Abstract
In an example, aspects of this disclosure relate to a method of coding video data that includes determining a quantization parameter (QP) for coding residual video data, where the QP is indexed to a quantizer step size. The method also includes determining a quantization scaling value for scaling the quantizer step size, and applying the quantization scaling value scaling to the quantizer step size. The method also includes coding the residual video data using the scaled quantizer step size.
Claims38
A method of coding video data, the method comprising:
- determining, for a block of residual video data, a quantization parameter (QP) from a plurality of QPs for coding the residual video data, wherein each QP of the plurality of QPs is indexed to a predetermined quantizer step size, and wherein the predetermined quantizer step size is fixed;
- coding, for the block of the residual video data, one or more syntax elements that indicate a value for a quantization scaling value that is separate from the predetermined quantizer step size for scaling the predetermined quantizer step size indexed to the determined QP;
- applying the quantization scaling value to the predetermined quantizer step size to determine a scaled quantizer step size, and wherein:
- applying the quantization scaling value to the predetermined quantizer step size causes the predetermined quantizer step size to increase to the scaled quantizer step size, wherein the scaled quantizer step size corresponds to less quantization than an amount of quantization associated with a next higher QP relative to the QP;
- or
- applying the quantization scaling value to the predetermined quantizer step size causes the predetermined quantize step size to decrease to the scaled quantizer step size, wherein the scaled quantizer step size corresponds to more quantization than an amount of quantization associated with a next lower QP relative to the QP;
- and
- de-quantizing one or more transform coefficients of the block of residual video data using the scaled quantizer step size.
5 more elements
An apparatus for coding video data, the apparatus comprising:
- a memory configured to store residual video data;
- and
- one or more processors configured to:
- determine, for a block of residual video data, a quantization parameter (QP) from a plurality of QPs for coding the residual video data, wherein each QP of the plurality of QPs is indexed to a predetermined quantizer step size, and wherein the predetermined quantizer step size is fixed;
- code, for the block of the residual video data, one or more syntax elements that indicate a value for a quantization scaling value that is separate from the predetermined quantizer step size for scaling the predetermined quantizer step size indexed to the determined QP;
- apply the quantization scaling value to the predetermined quantizer step size to determine a scaled quantizer step size, and wherein:
- to apply the quantization scaling value to the predetermined quantizer step size, the one or more processors cause the predetermined quantizer step size to increase to the scaled quantizer step size, wherein the scaled quantizer step size corresponds to less quantization than an amount of quantization associated with a next higher QP relative to the QP;
- or
- to apply the quantization scaling value to the predetermined quantizer step size, the one or more processors cause the predetermined quantize step size to decrease to the scaled quantizer step size, wherein the scaled quantizer step size corresponds to more quantization than an amount of quantization associated with a next lower QP relative to the QP;
- and
- de-quantize one or more transform coefficients of the block of residual video data using the scaled quantizer step size.
8 more elements
A method of coding video data, the method comprising:
- selecting between at least a first quantization granularity and a second, different quantization granularity, wherein quantization granularity comprises an extent to which a predetermined amount of quantization for transform coefficient coding is subdivided, wherein the predetermined amount of quantization comprises a range of quantization from a minimum amount of quantization to a maximum amount of quantization, wherein the first quantization granularity indexes a first number of quantization parameters (QPs) to a first quantization step size, and wherein the second quantization granularity indexes a second number of QPs that is larger than the first number of QPs to a second quantization step size;
- determining an actual QP associated with the selected quantization granularity for one or more transform coefficients associated with residual video data based on a delta QP, the delta QP determined as a difference between the actual QP and, when the reference QP has a different quantization granularity than the actual QP, a reference QP mapped to the quantization granularity of the actual QP;
- and
- coding the one or more transform coefficients associated with the residual video data using the actual QP associated with the selected quantization granularity.
1 more element
An apparatus for coding video data, the apparatus comprising:
- a memory configured to store one or more transform coefficients;
- and
- one or more processors configured to:
- select between at least a first quantization granularity and a second, different quantization granularity, wherein quantization granularity comprises an extent to which a predetermined amount of quantization for transform coefficient coding is subdivided, wherein the predetermined amount of quantization comprises a range of quantization from a minimum amount of quantization to a maximum amount of quantization, wherein the first quantization granularity indexes a first number of quantization parameters (QPs) to a first quantization step size, and wherein the second quantization granularity indexes a second number of QPs that is larger than the first number of QPs to a second quantization step size;
- determining an actual QP associated with the selected quantization granularity for the one or more transform coefficients based on a delta QP, the delta QP determined as a difference between the actual QP and, when the reference QP has a different quantization granularity than the actual QP, a reference QP mapped to the quantization granularity of the actual QP;
- and
- code the one or more transform coefficients associated with residual video data using the actual QP associated with the selected quantization granularity.
4 more elements
An apparatus for coding video data, the apparatus comprising:
- means for determining, for a block of residual video data, a quantization parameter (QP) from a plurality of QPs for coding the residual video data, wherein each QP of the plurality of the QPs is indexed to a predetermined quantizer step size, and wherein the predetermined quantizer step size is fixed;
- means for coding, for the block of the residual video data, one or more syntax elements that indicate a value for a quantization scaling value that is separate from the predetermined quantizer step size for scaling the predetermined quantizer step size indexed to the determined QP;
- means for applying the quantization scaling value to the predetermined quantizer step size to determine a scaled quantizer step size, and wherein:
- the means for applying the quantization scaling value to the predetermined quantizer step size causes the predetermined quantizer step size to increase to the scaled quantizer step size, wherein the scaled quantizer step size corresponds to less quantization than an amount of quantization associated with a next higher QP relative to the QP;
- or
- the means for applying the quantization scaling value to the predetermined quantizer step size causes the predetermined quantize step size to decrease to the scaled quantizer step size, wherein the scaled quantizer step size corresponds to more quantization than an amount of quantization associated with a next lower QP relative to the QP;
- and
- means for de-quantizing one or more transform coefficients of the block of residual video data using the scaled quantizer step size.
5 more elements
A non-transitory computer-readable storage medium having instructions stored thereon that, when executed, cause one or more processors to:
- determine, for a block of residual video data, a quantization parameter (QP) from a plurality of QPs for coding the residual video data, wherein each QP of the plurality of QPs is indexed to a predetermined quantizer step size, and wherein the predetermined quantizer step size is fixed;
- code, for the block of the residual video data, one or more syntax elements that indicate a value for a quantization scaling value that is separate from the predetermined quantizer step size for scaling the predetermined quantizer step size indexed to the determined QP;
- apply the quantization scaling value to the predetermined quantizer step size to determine a scaled quantizer step size, and wherein:
- to apply the quantization scaling value to the predetermined quantizer step size, the instructions cause the one or more processors to cause the predetermined quantizer step size to increase to the scaled quantizer step size, wherein the scaled quantizer step size corresponds to less quantization than an amount of quantization associated with a next higher QP relative to the OP;
- or
- to apply the quantization scaling value to the predetermined quantizer step size, the instructions cause the one or more processors to cause the predetermined quantize step size to decrease to the scaled quantizer step size, wherein the scaled quantizer step size corresponds to more quantization than an amount of quantization associated with a next lower QP relative to the QP;
- and
- de-quantize one or more transform coefficients of the block of residual video data using the scaled quantizer step size.
5 more elements
An apparatus for coding video data, the apparatus comprising:
- means for selecting between at least a first quantization granularity and a second, different quantization granularity, wherein quantization granularity comprises an extent to which a predetermined amount of quantization for transform coefficient coding is subdivided, wherein the predetermined amount of quantization comprises a range of quantization from a minimum amount of quantization to a maximum amount of quantization, wherein the first quantization granularity indexes a first number of quantization parameters (QPs) to a first quantization step size, and wherein the second quantization granularity indexes a second number of QPs that is larger than the first number of QPs to a second quantization step size;
- means for determining an actual QP associated with the selected quantization granularity for the one or more transform coefficients based on a delta QP, the delta QP determined as a difference between the actual QP and, when the reference QP has a different quantization granularity than the actual QP, a reference QP mapped to the quantization granularity of the actual QP;
- and
- means for coding one or more transform coefficients associated with residual video data using the actual QP associated with the selected quantization granularity.
1 more element
A non-transitory computer-readable storage medium having instructions stored thereon that, when executed, cause one or more processors to:
- select between at least a first quantization granularity and a second, different quantization granularity, wherein quantization granularity comprises an extent to which a predetermined amount of quantization for transform coefficient coding is subdivided, wherein the predetermined amount of quantization comprises a range of quantization from a minimum amount of quantization to a maximum amount of quantization, wherein the first quantization granularity indexes a first number of quantization parameters (QPs) to a first quantization step size, and wherein the second quantization granularity indexes a second number of QPs that is larger than the first number of QPs to a second quantization step size;
- determining an actual QP associated with the selected quantization granularity for the one or more transform coefficients based on a delta QP, the delta QP determined as a difference between the actual QP and, when the reference QP has a different quantization granularity than the actual QP, a reference QP mapped to the quantization granularity of the actual QP;
- and
- code one or more transform coefficients associated with residual video data using the actual QP associated with the selected quantization granularity.
1 more element
Dependencies are inferred from the claim text.